[llvm] r264224 - [PS4] Guarantee an instruction after a 'noreturn' call.

Paul Robinson via llvm-commits llvm-commits at lists.llvm.org
Wed Mar 23 17:10:04 PDT 2016


Author: probinson
Date: Wed Mar 23 19:10:03 2016
New Revision: 264224

URL: http://llvm.org/viewvc/llvm-project?rev=264224&view=rev
Log:
[PS4] Guarantee an instruction after a 'noreturn' call.

We need the "return address" of a noreturn call to be within the
bounds of the calling function; TrapUnreachable turns 'unreachable'
into a 'ud2' instruction, which has that desired effect.

Differential Revision: http://reviews.llvm.org/D18414

Added:
    llvm/trunk/test/CodeGen/X86/ps4-noreturn.ll
Modified:
    llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
    llvm/trunk/test/CodeGen/X86/br-fold.ll

Modified: llvm/trunk/lib/Target/X86/X86TargetMachine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86TargetMachine.cpp?rev=264224&r1=264223&r2=264224&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86TargetMachine.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86TargetMachine.cpp Wed Mar 23 19:10:03 2016
@@ -119,7 +119,9 @@ X86TargetMachine::X86TargetMachine(const
   // after a call to 'noreturn' function.
   // To prevent that, we emit a trap for 'unreachable' IR instructions.
   // (which on X86, happens to be the 'ud2' instruction)
-  if (Subtarget.isTargetWin64())
+  // On PS4, the "return address" of a 'noreturn' call must still be within
+  // the calling function, and TrapUnreachable is an easy way to get that.
+  if (Subtarget.isTargetWin64() || Subtarget.isTargetPS4())
     this->Options.TrapUnreachable = true;
 
   // By default (and when -ffast-math is on), enable estimate codegen for

Modified: llvm/trunk/test/CodeGen/X86/br-fold.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/br-fold.ll?rev=264224&r1=264223&r2=264224&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/br-fold.ll (original)
+++ llvm/trunk/test/CodeGen/X86/br-fold.ll Wed Mar 23 19:10:03 2016
@@ -2,6 +2,7 @@
 ; RUN: llc -mtriple=x86_64-pc-linux < %s | FileCheck  -check-prefix=X64_LINUX %s
 ; RUN: llc -mtriple=x86_64-pc-windows < %s | FileCheck  -check-prefix=X64_WINDOWS %s
 ; RUN: llc -mtriple=x86_64-pc-windows-gnu < %s | FileCheck  -check-prefix=X64_WINDOWS_GNU %s
+; RUN: llc -mtriple=x86_64-scei-ps4 < %s | FileCheck -check-prefix=PS4 %s
 
 ; X64_DARWIN: orq
 ; X64_DARWIN-NEXT: %bb8.i329
@@ -15,6 +16,9 @@
 ; X64_WINDOWS_GNU: orq %rax, %rcx
 ; X64_WINDOWS_GNU-NEXT: ud2
 
+; PS4: orq %rax, %rcx
+; PS4-NEXT: ud2
+
 @_ZN11xercesc_2_513SchemaSymbols21fgURI_SCHEMAFORSCHEMAE = external constant [33 x i16], align 32 ; <[33 x i16]*> [#uses=1]
 @_ZN11xercesc_2_56XMLUni16fgNotationStringE = external constant [9 x i16], align 16 ; <[9 x i16]*> [#uses=1]
 

Added: llvm/trunk/test/CodeGen/X86/ps4-noreturn.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/ps4-noreturn.ll?rev=264224&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/ps4-noreturn.ll (added)
+++ llvm/trunk/test/CodeGen/X86/ps4-noreturn.ll Wed Mar 23 19:10:03 2016
@@ -0,0 +1,38 @@
+; RUN: llc < %s -mtriple=x86_64-scei-ps4 | FileCheck %s
+
+declare i32 @personality(...)
+
+; Check that after the (implicitly noreturn) unwind call, there is
+; another instruction. It was easy to produce 'ud2' so we check for that.
+define void @foo1() personality i32 (...)* @personality {
+; CHECK-LABEL: foo1:
+; CHECK: .cfi_startproc
+; CHECK: callq bar
+; CHECK: retq
+; Check for 'ud2' between noreturn call and function end.
+; CHECK: callq _Unwind_Resume
+; CHECK-NEXT: ud2
+; CHECK-NEXT: .Lfunc_end0:
+    invoke void @bar()
+        to label %normal
+        unwind label %catch
+normal:
+    ret void
+catch:
+    %1 = landingpad { i8*, i32 } cleanup
+    resume { i8*, i32 } %1
+}
+
+declare void @bar() #0
+
+; Similar check after an explicit noreturn call.
+define void @foo2() {
+; CHECK-LABEL: foo2:
+; CHECK: callq bar
+; CHECK-NEXT: ud2
+; CHECK-NEXT: .Lfunc_end1:
+    tail call void @bar()
+    unreachable
+}
+
+attributes #0 = { noreturn }




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